FR2812446A1 - Vehicle windscreen wiper rest position return switch container having container with upper rotation mounted control unit and non contacting detector controlling wiper rest return position. - Google Patents

Abstract

The windscreen wiper control mechanism container (12) has a control unit mounted in rotation on the container. There is a non contact type Hall effect detector detecting the control mechanism rotation position corresponding to the wiper rest position.

Description

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  NON-REVERSIBLE RETURN SWITCH TO THE POSITION OF

REFITTING A WIPER MOTOR

  The present invention relates, in general, to windscreen wipers for vehicles, and, more specifically, to switches for returning to

  wiper rest position.

  In a wiper control unit for vehicles, the wipers are provided with an automatic stopping device in the retracted or rest position which allows the wiper blades to return to their rest position regardless of when a user opens a switch

  wiper control during the wiping cycle.

  In a typical switch for returning to the wiper rest position, an electrically conductive plate is provided with electrically conductive and electrically non-conductive portions or traces. One (s) electrical contact (s) fixed (s) or otherwise driven (s) by the control mechanism coupled to the wiper control motor cooperates (s) with the electrically conductive plate to form a switch that opens and closes an electrical circuit to the electrical terminals of the wiper control motor so that even when the user opens the wiper control switch during the wiping cycle, the electrically conductive plate and the contact (s) form a circuit which allows the wiper motor to continue returning the wiper blades to their rest position. The contact (s) is (are) typically driven (s) or moved (s) by the control mechanism between the two positions, one forming a closed switch with the electrically conductive plate, and the other forming

an open circuit.

  However, the wiper control mechanisms

  glass for older vehicles of this type have -2 - some problems. First, the contact (s) of the switch for returning to the rest position is (are) moved (s) in and out of contact with the conductive traces on the conductive plate several times during a scanning operation . This causes contact wear and requires a more robust design of contacts and wipers which adds to the cost of manufacturing vehicle wipers. Despite such robust designs, contacts are still likely to wear out due to long-term use, which could cause discontinuity or

  loss of full contact with the conductive plate.

  In addition, the contacts are sensitive to grease and other foreign bodies which can settle on the conductive plate or on the contacts, which can also lead to loss of contact.

  electric with the conductive plate.

  Most importantly, prior wiper controllers with conventional return-to-home switches are frequently subject to vibration when snow or other obstructions on a lower portion

  of the vehicle windshield prevents the wiper blades

  ice to return to their rest position. In this situation, the control mechanism of the wiper motor is subjected to a force which acts in a direction opposite to the normal direction of rotation of the control mechanism. Snow or any other obstacle constitutes an elastic force on the wiper blades which pushes the movement of the wiper blades and of the control mechanism attached out of the rest position. Therefore, as soon as the wiper control motor is cut by the switch returning to the rest position, the reverse movement of the wiper blades and the control mechanism causes the contact (s) ) to return to contact with the conductive portion of the conductive plate, thereby again applying an electric current to the wiper control motor and causing -3 - the control motor to restart the movement of the brushes wiper in the direction of the rest position. The blades are then placed in oscillation between the rest and non-rest states, which could cause damage to the wiper blades or to the wiper control linkages, as well as electrical wear of the electrical contacts and / or the wiper control motor, while giving rise to unbearable noise or vibration for

the occupants of the vehicle.

  Therefore, it would be desirable to provide a wiper control apparatus which solves the aforementioned problems encountered by the switches for returning to the rest position of the wipers, which are discussed above. It would also be desirable to provide a return to home position switch mechanism for a vehicle wiper control apparatus which eliminates movable contact portions for the return to home position switch. It would also be desirable to provide a wiper controller having a single model of housing and control mechanism for different wiper applications, including intermittent and non-intermittent wiper devices. The present invention is an improved wiper control apparatus which is characterized by a non-electric contact position detection or sensor for detecting the retracted or rest position of the wiper blades. In another aspect, a portion of the non-electric contact sensor is supported on a rotating cam mounted in the wiper control unit which is rotated by the control mechanism via engagement members mutual on the control mechanism and on the cam in the normal direction of rotation of the control mechanism. A backward control of the -4 control mechanism does not result in reverse rotation of the cam, thereby preventing vibration of the

windscreen wipers.

  In a specific aspect of the present invention, the wiper apparatus includes a rotary control mechanism adapted to be coupled to a wiper for controlling the wipers, a housing with the control mechanism rotatably mounted to the inside the housing, and a non-contact position sensor arranged in cooperation between the control mechanism and the housing in order to detect a rotational position of the control mechanism

  corresponding to the rest position of the wiper.

  Specifically, the position detector consists of a magnetically sensitive sensor mounted in the housing, a magnet movably disposed in the housing on a path of motion intersection with the sensor. The magnet is movable with the control mechanism, with the sensor detecting each

passage of the magnet in front of him.

  The magnet is mounted on the control mechanism in a first aspect of the present invention. In an alternative aspect, a cam is rotatably mounted in the housing. In this aspect, the magnet is mounted on the cam. Mutually engaging elements on the control mechanism and on the cam cause the cam to rotate in the normal direction of rotation of the control mechanism. The mutual engagement elements are, in a first example, projections formed on the cam and on the control mechanism which are on rotary paths which

intersect.

  The cam is arranged for one-way rotation only in the normal direction of rotation of the control mechanism. Any backward control of the control mechanism caused by the wiper blades striking an obstacle as they move towards their rest position separates the mutual engagement elements on the control mechanism and on the cam, leaving the cam in the rest position and preventing a new application of an electric current to the

wiper control.

  The wiper control device of the present invention solves several problems encountered by prior wiper devices, in particular the wear of the contacts, the oscillatory vibrations and the movement of the wipers when an obstacle prevents the wiper blades from fully reaching their retracted or rest position. The magnetic non-contact sensor employed in the present invention eliminates direct electrical contact from previous wiper models, thereby increasing the reliable long-term use of the wiper controller of this invention. In the aspect of the invention in which the magnet of the position detector of the invention is mounted on the cam rotatably supported in the wiper control box, the cam is arranged for unidirectional rotation only , thereby eliminating any further application of electric current to the wiper control motor, even if the wiper control mechanism is moved backward when the wiper blades strike an obstacle when moving towards their position

fully returned or rested.

  The characteristics, advantages and uses of all kinds of the present invention will appear more

  clearly referring to the detailed description

  which follows, as well as to the drawings, in which FIG. 1 is an exploded perspective view of a

  portion of a wiper control unit housing

  glass containing a switch for returning to the non-contact rest position in accordance with the present invention; Figure 6 is a perspective view of the wiper control apparatus shown in Figure 1, shown in an assembled position; Figure 3 is a perspective view from above of a switch trigger cam assembly shown in Figure 1; Figure 4 is a perspective view from below of the switch trigger cam assembly shown in Figure 3; Figure 5 is a cross-sectional view taken generally along line 5-5 in Figure 2; and Figure 6 is a side elevational view, similar to that of Figure 5, but showing an alternative aspect of the position sensor of the present invention. Referring now to the drawings, and Figures 1, 2 and 5 in particular, there is shown a portion of a wiper control mechanism or apparatus generally designated by the

number 10.

  A cup-shaped housing 12 is provided with a peripheral side wall 14 which surrounds an interior cavity or chamber 16. Terminals 18 are mounted in the interior cavity 16 and communicate with external pins 20 in order to transmit signals

  outside the housing 12.

  The terminals 18 engage connectors 22 mounted on a printed circuit 24 which can be disposed inside the interior cavity 16 in the housing 12. The connectors 22 provide electrical contact between the terminals 18 and various conductive traces formed in the circuit PCB 24 and electrical components mounted on PCB 24. By way of example only, the aspect of the present invention shown in Figures 1 and 2 includes a PCB 24 which provides a wiper control. intermittent ice. It should be understood that the present invention can also be used with a non-intermittent wiper control assembly in which the printed circuit 24, or at least the wiper control circuit

  intermittent on the printed circuit can be eliminated.

  As shown in Figures 1, 2 and 5, a pin 30 is mounted on a lower portion of the

  housing 12 inside the interior chamber 16.

  The pin 30 can be slid through an opening 32 in the printed circuit 24 in order to fix the printed circuit 24 inside the interior chamber 16 of the

housing 12.

  It should be understood that the external configuration of the housing 12 as well as the configuration of the internal cavity 16 in the housing 12 and of the printed circuit 24 are only examples since these components may have other configurations. However, an important advantage of the present invention is that only one model of housing as well as one model of corresponding control mechanism can be used for both control devices

  intermittent and non-intermittent wipers.

  This provides a common pattern for most wiper control assemblies, which reduces

this fact the production costs.

  As shown in Figure 5, and as is conventional in a wiper control apparatus, a control mechanism 40 may be juxtaposed above the interior chamber 16 in the housing 12. The mechanism 40 is mounted around its own spindle or pivot support 42 in a separate control box to which the control motor is attached, not shown. The control box is fixed to the side wall 14 of the box 12. Since the control box and the control motor are of the conventional type and well known in the current art, their characteristics are not shown in FIG. 5 for clarity of

  understanding of the present invention.

  The control mechanism 40 is rotated by a worm gear connected to or mounted on the output shaft of the wiper control motor, neither of which is shown in Figure 5. The rotation of the control mechanism 40 is printed on the output shaft 42 which is connected to the wiper crank arm, not shown. The crank arm is part of a conventional wiper linkage, which converts the rotational movement of the output shaft 42 into an oscillating movement of the wiper arms and wiper blades. attached across the surface of a

vehicle window.

  During the oscillatory movement, the wipers

  The windows, which include the wiper blades and the wiper arm assembly, move between an extended position and a retracted position. The retracted position is also known as the rest position for wiper models that do not have a retracted or separate row parking position. It is necessary to interrupt the application of electric current to the wiper control motor when the wipers have reached the rest position. So it becomes necessary to detect when the wiper blades

reach their retracted position.

  In accordance with the present invention, a single position sensor is provided in the wiper control apparatus to detect when the wipers reach the retracted or rest position. The position sensor generates a signal which is used to interrupt the application of an electric current to the control motor in order to prevent movement

  additional wiper blades.

  The position detector of the present invention preferably comprises a permanent magnet 48 and a magnetic field detector 50. Preferably, the magnetic field detector 50 is a detector or

  Hall effect magnetic field sensor.

  In the example of the present invention shown in Figures 1, 2 and 5, the Hall effect sensor 50 is mounted on the printed circuit 24. The position detector of the present invention is offered in two different configurations. A first aspect of the detector is shown in Figures 1 to 5, in which a switch trigger cam 54 is rotatably mounted around the pin 30 in the interior chamber 16 of the housing 12. It should be understood that the

  specific description which follows of the structure of the

  switch trigger cam 54 is done as an example only, since other cam configuration can be used

switch tripping 54.

  Therefore, as shown in detail in Figures 3 to 5, the switch trigger cam 54 includes an outer side wall 60, preferably having a circular cross section, although other configurations are also possible. A flange 62 projects from one end of the side wall 60 and ends with an engagement element

  mutual, such as a projection or support 64.

  An inner wall 66 is formed inside the side wall 60 and is spaced from the end of the side wall 60 supporting the flange 62. A bore 68 extends through the wall 66 towards an opposite end of the side wall 60. A plurality of springs or elastic fingers 70 are formed or molded as a unit as part of the wall 66 and extend through the bore 68. The fingers 70 provide a resilient force for providing friction and resistance against freewheel rotation of the release cam

  switch 54 around pin 30.

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  A bore 72 is formed in the switch triggering cam 54 near the side wall 60, as shown in FIGS. 4 and 5. The bore 72 receives a permanent magnet 74 which is preferably of cylindrical configuration, by way of example only. As shown in Figures 4 and 5, one end 76 of the magnet 74 is exposed through one end of the switch trigger cam 54. The exposed end 76 of the magnet 74 is spaced from the sensor 50 as shown in Figure 5 and is positioned so as to be in a rotary path of intersection with the sensor 50 during rotation

  of the switch trigger cam 54.

  A retaining device or clamp 80 can be mounted on the upper end of the spindle 30 in engagement with the wall 66 in the switch trigger cam 54 in order to push the switch trigger cam 54 into position. on the

pin 30.

  When the switch trigger cam 54 is mounted on pin 30, as shown in Figure 5, the projection 64 at the end of the flange 62 will be in a rotary path intersecting that of an element of corresponding mutual commitment or

  projection 84 formed on the control mechanism 40.

  In this way, since the control mechanism 40 is driven in a normal direction of rotation, the projection 84 on the control mechanism 40 will engage the projection 64 on the switch trigger cam 54, thereby rotating the cam trigger switch 54 around the spindle 30 in the same direction of rotation as the control mechanism 40. During each rotation, the magnet 74 supported by the switch trigger cam 54 will pass through the sensor 50. This passage will be detected by the sensor 50 which then generates an output signal to the control circuit of the wiper control apparatus, not shown. Yes

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  the driver of the vehicle has moved the lever or the wiper stop control switch to an "open" position, the output signal

  from sensor 50, which indicates that the wipers

  windows have reached the retracted or rest position, will be used by the wiper control circuit to disconnect the electric current on the wiper control motor, thereby leaving the brushes

  wiper in the retracted or rest position.

  An important advantage of using the switch trigger cam 54 shown in the

  Figures 3 to 5 occur when the wiper blades

  ice encounter an obstacle when moving towards the retracted position, such as an accumulation of snow on the hood of the vehicle. Although the torque produced by the wiper control motor may be sufficient to move the wiper blades to the rest position, the obstacle or snow may generate sufficient force to drive back the wiper blades away from the stowed position in a reverse direction of movement. This command backwards will be transmitted to the wiper blades, and to the wiper control linkage as well as to the crank arm to the control mechanism which then rotates in an opposite direction of rotation relative to its normal direction of rotation. This reverse movement of the control mechanism could cause the contacts in a wiper control apparatus of the prior art to come into contact again with the conductive traces on the control mechanism or the printed circuit and to reapply a electric current on the control motor, causing the wiper blades to reverse direction and move again towards the home position. This results in an oscillating action of the wiper blades, unbearable vibrations as well as a potential occurrence of a motor failure.

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  control or contacts, or even damage to the

  wiper control linkage.

  In the aspect of the invention shown in Figure 1, the use of the switch trigger cam 54 eliminates any backward control. The projection 84 on the control mechanism 40 will engage the projection 64 on the switch triggering cam 54 only in the normal direction of rotation of the control mechanism 40. If the control mechanism 40 is controlled backwards, like this is described above, when the wiper blades meet an obstacle when they reach the retracted or rest position, the projection 84 will disengage and will move away from the projection 64 on the switch trigger cam 54, thereby leaving the switch trigger cam 54 in the last position corresponding to the wipers in the retracted position following a signal from the sensor 50 used by the wiper control circuit -window in order to disconnect the electric current on the wiper control motor. In this case, the wiper control motor remains disconnected from the electrical current and does not communicate the oscillatory movement of the wiper blades in and out of the position.

  reentry or rest, as in the towel models

previous ice.

  Another aspect of the present invention is shown in Figure 6, in which a non-contact sensor is always employed in order to detect the rotation of the control mechanism 40 coinciding with the arrival of the wiper blades in the retracted position. or rest. However, this aspect of the invention is characterized by the absence of unidirectional rotation of the magnet as provided by the use of the trigger cam.

switch 54.

  As shown in Figure 6, in this aspect of the invention, the magnet 74 is mounted in the

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  control mechanism 40 ', for example in a portion of the central hub of the control mechanism. However, the first end of the magnet 74 is still positioned so as to cover and pass through the sensor 50 mounted inside the housing 12 during the rotation of the control mechanism 40 'in order to indicate that the brushes wipers have reached the

retracted or rest position.

  Thus, a unique wiper blade position sensor has been disclosed which uses a non-contact position sensor to detect the arrival of the wiper blades in the retracted or rest position. The use of the non-contact sensor increases the reliable long-term use of the wiper control apparatus of the present invention by eliminating the electrical contacts which are liable to wear, experience interruption of contact due to external materials, etc. In

  a first aspect, the wiper control apparatus

  window also includes unidirectional position sensor operation, which eliminates backward control of the home position switch as well as oscillatory motion, unbearable vibrations and potential damage to the wiper control unit ice which

  as a result, as with wiper systems

previous ice.

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Claims (7)

claims   1. A wiper control apparatus 10 having a wiper rest position, the apparatus comprising: a housing 12; a rotary control mechanism 40 adapted to be coupled to a wiper for controlling the wiper, a control mechanism 40 rotatably mounted in the housing 12; and a non-contact position detector arranged in cooperation between the control mechanism and the housing in order to detect a rotational position of the control mechanism 40 corresponding to the   the wiper rest position.   2. A wiper control apparatus 10 according to claim 1, wherein the position detector comprises: a magnetically sensitive sensor 50 mounted in the housing 12; and a magnet movably disposed in the housing 12 in a path of movement intersection relative to the sensor 50, the magnet being movable with the control mechanism 40, the sensor   detecting each pass of the magnet in front of him.   3. The wiper control apparatus 10 according to claim 1, wherein the magnet   is mounted on the control mechanism 40.   4. The control apparatus 10 according to claim 1, further comprising: a cam 54 rotatably mounted in the housing 12, the magnet being supported by the cam 54; and mutual engagement elements supported by the control mechanism 40 and the cam 54 to rotate the cam 54 in concert with the - 15 -   rotation of the control mechanism 40 in the direction of   normal rotation of the control mechanism 40.   5. A wiper control apparatus 10 according to claim 4, wherein the mutual engagement elements comprise: a projection 84 supported by the control mechanism 40; and a projection 64 supported by the cam 54, the projections 84, 64 on the control mechanism and on the cam being located on cutting movement.   6. A wiper control apparatus according to claim 4, wherein: the mutual engagement members provide only one-way rotation of cam 54.   7. The wiper control apparatus 10 according to claim 4, wherein: the mutual engagement member on the control mechanism 40 engages the mutual engagement member on the cam 54 only in one direction of   normal rotation of the control mechanism 40.